Curl corrector apparatus for operating on a continuous web

ABSTRACT

Curl corrector apparatus for operating on a continuous travelling web of paper, cardboard or like material, is arranged between two pairs of web guide rollers. Two similar curl corrector rods are rotatably mounted parallel to each other and to the web guide rollers between the latter. Means are provided for shifting these corrector rods to opposite sides of the straight line path between the guide rollers so that one or the other operates to correct curl. Support rollers back-up these corrector rods, which may also be urged together to provide a nip for the web. The corrector rods are guided by pivoting links or rails.

[451 Dec. 18, 1973 United States Patent (191 Lindstaedt et al.

72/164 72/164 Helminen.............................. 93/l R 3,643,4872/1972 2,303,096 1l/1942 Thaden........ 3,543,365 12/1970 CURL CORRECTORAPPARATUS FOR OPERATING ON A CONTINUOUS WEB [75] Inventors: Horst KarlLindstaedt, Bristol;

Egg? fg Webb Somerset both Primary Examiner--Andrew R. Juhasz gAssistant Examiner-Leon Gilden [73] Assignee: Masson Scott ThrissellEngineering Att0rneylrvin S. Thompson et a].

Limited, Bristol, England Mar. 10, 1972 [57] ABSTRACT Curl correctorapparatus for operating on a continu- [22] Filed:

211 App]. No.: 233,511

ous' travelling web of paper, cardboard or like mate- [301 ForeignAppficafion p i i Data rial, is arranged between two pairs of web guiderol- Mar m 197] Gram Britain lers. Two similar curl Corrector rods arerotatably mounted parallel to each other and to the web guide rollersbetween the latter. Means are provided for 04 06 l] a n7 3; BR

mm "3 m9 [51] Int. [58] Field of Search..

[56] References Cited UNITED STATES PATENTS urged together to provide anip for the web. The corrector rods are guided by pivoting links orrails.

3 442 I08 5/1969 Miller 72/164 2.037.040 7/1937 MlCdn 72/164 X 6 Claims,6 Drawing Figures PATENTED [m1 8 197a SHEET 1 0F 4 PATENTEUUEBI 8 19153,779,138

sum 2' or 4 PATENTEDBEBI 1m 3.772%138 SHEET 3 0f 4 FIG. 6.

PATENTEB UElH 81973 sum u or a} CURL CORRECTOR APPARATUS FOR OPERATINGON A CONTINUOUS WEB This invention relates to curl corrector apparatusfor operating on continuous travelling webs of paper, cardboard or likematerial. When such material is unwound from a reel, it has an inherenttendency to curl in the same direction as it has been previously wound,and this tendency becomes particularlyapparent when the material is cutinto individual sheets. Previously proposed curl corrector apparatuscomprises a rotatable bar of comparatively small diameter over which,the web is deflected in the opposite sense to its tendency to curl. Thecurl corrector rod is normally provided with support rolls on its sideremote from the web to reduce bending of the rod.

The sense in which the reel is unwound and consequently the direction ofcurl of the web may be in either direction according to the number ofprevious occasions on which the web has been reeled during preliminaryprocessing. The known curl corrector apparatus can, however, only dealwith curl in one direction and so it is necessary for a reel with theopposite direction of curl to be rewound before that curl correctorapparatus can be used.

According to the present invention a curl corrector apparatus foroperating on a continuous travelling web of paper, cardboard or likematerial, comprises two similar curl corrector rods mounted on oppositesides of the path of the web between two pairs of web guide rollers anddisplaceable transversely to the path of the web, so that the curlcorrector rods are respectively capable of deflecting the web toopposite sides of the straight line path between the pairs of guiderollers, for correction of curl in either direction.

The two curl corrector rods may be rotatably carried by a commonmounting element at each end displaceable transversely to the path ofthe web. The common mounting elements may also carry two pairs ofsupport rolls, each pair being arranged side by side and contacting thecurl corrector rod on its side away from the web.

Preferably the mounting elements are guided in their transversedisplacement so that the angle formed by the deflected path of the webis always substantially bisected by the plane which passes through theaxis of the curl corrector rod which is deflecting the web and passesequidistantly between its support rolls.

For example the mounting elements may be guided by means of a pivotallinkage comprising, for each mounting element, a pair of non-parallelswinging arms pivoted at one of their ends at spaced positions on afixed part of the apparatus adjacent to one of the pairs of guiderollers, and pivoted at their other ends at spaced positions on therespective mounting element. Alternatively the two mounting elements mayeach be formed by a pivotal arm which is pivoted at one endto a fixedpart of the apparatus adjacent to one of the pairs of guide rollers andcarries one end of each of the two curl corrector rods at its other end,the support rolls being carried by the pivotal arms through links whichare pivoted to the arms on the axes of the respective curl correctorrods and which are connected by further links to spaced pivots on thefixed part. In a further alternative, the mounting elements may beguided on rails extending transversely to the straight line path betweenthe pairs of guide rollers.

Means may be provided for urging the two curl corrector rods against oneanother, so that the one which is not acting as a curl corrector at anygiven time will serve as an additional support roll! for the one whichis so acting.

The invention may be performed in various ways and some specificembodiments thereof will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic vertical section through a curl correctorappararus,

FIG. 2 is a similar section through a second form of apparatus,

FIG. 3 is a similar view of a third embodiment,

FIG. 4 is a similar view of a fourth embodiment,

FIG. 5 is a partial underneath plan view of the embodiment of FIG. 4,and

FIG. 6 is a diagrammatic vertical section through a further embodiment.

In the apparatus shown in FIG. 1, the web W is drawn from a reel (notshown) to the left hand side of the figure, passes between a pair ofguide rolls 10,1 I mounted in a fixed part 12 of the apparatus and isdrawn off be tween a further pair of guide rolls 13,14 mounted on thefixed part 12. From there the web is directed to a transverse cuttingapparatus (not shown).

A pair of rotatable circular-section curl corrector rods 16,17 aremounted at their respective ends in a pair of vertical plate-likemounting elements 18, of which only one is visible in FIG. 1. It isshown in one curl-correcting position in full lines and in alternativepositions in broken lines. Each curl corrector rod 16,17 is supported bya respective pair of backing or support rolls 19,20, mounted so as tocontact the respective curl corrector rod on its side remote from theweb W. Each pair of support rolls 19,20 is formed by a series of pairsof short aligned rolls in known manner, each individual pair of rollsbeing mounted in a respective bracket 191,201. The brackets 191,201 aremounted on transverse beams 192,202 secured at their ends to theplate-like mounting elements 18.

The curl corrector rods 16,17 are not positively located in the mountingelements 18 but have limited freedom to float laterally. Spherical ballbearing supports (not shown) at'each end'confine the rods axially.

Each of the rods 16,17 is prevented from falling out of place by theother rod and by its support rolls.

Each of the plate-like elements 18 is supported at 25,26 at the ends ofa pair of non-parallel pivoted arms 21,22 whose other ends are pivotedat 23,24 respectively on the fixed part 12 of the apparatus. The spacingbetween the pivots 25,26 of the arms 21,22 on the plates 18 is greaterthan the spacing between their pivots 23,24 on the part 12;, so that theplane 27 which passes through the axes of the curl corrector rods 16,17and is equidistant from the rollers of the respective pairs 19,20 alwaysbisects the angle made by the web W as it is deflected by either of thecurl corrector rods 16,17. A leadscrew actuator 15 having a protectivebellows 151 is connected to each of the plate-like elements 18 fordisplacing them transversely to the web W.

It will be realised that, by thus displacing the platelike mountingelements 18 transversely to the web W on the pivotal arms 21,22 the webW can be deflected either upwardly or downwardly so as to correct curlin either direction.

The embodiment of FIG. 2 is generally similar to that of FIG. 1 exceptthat the two curl corrector rods 16,17 are mounted at each end in one ofa pair of common pivoted arms 30, only one of which is visible. The arms30 are pivoted on a horizontal axis 37 on the fixed part 12, midwaybetween the axis 35,36 of the guide rollers 13,14. The support rolls19,20 are carried by the arms 30 through links 31,32 which are pivotedon the arms 30 coaxially with the curl corrector rods 16,17. The ends ofthe links 31,32 remote from the arms 30 are pivotally connected at 37,38to further links 33,34 pivoted on the fixed part 12 on the axes 35,36 ofthe guide rollers 13,14. 7

The distance between the pivot axes of each link 31,32 (i.e. thedistance between the axis of the rod 16 and pivot 37 and the distancebetween the axis of rod 17 and pivot 38) is greater than the distancebetweenthe axis 35,36 of the respective link 33,34 and the pivot axis 37of the arm 30, so that as in the previous embodiment the angle formed bythe deflected web W will always be bisected by the plane which passesthrough the curl corrector rod 16 or 17 currently in use and which alsopasses equidistantly between the support rolls of that rod.

In the embodiment of FIG. 3, the lower curl corrector rod 16 and itssupport rolls 19 are mounted at their respective ends in plate-likemounting elements 181 which are mounted on pivoted arms 21,22 as in theembodiment of FIG. 1. The upper curl corrector rod 17 and its supportrolls 20 are mounted at their ends in plates 182 slidable in themounting elements 181 parallel to the length of the latter, i.e.transversely to the web W.

Upper and lower jaws 41,42, having a common pivot 43 on the plate-likeelement 181, are connected respectively to the slidable plate 182 and tothe mounting element 181. The jaws 41,42 can be opened and closed by adiaphragm actuator 44. They are opened for insertion of the web W andmay be subsequently closed so that the rods 16,17 are urged against oneanother and the one which is at any time not acting as a curl correctorwill serve as a further support roller for the one that is so acting.Similar means may be provided in the embodiments of FIGS. 1 and 2 forurging the curl corrector rods 16,17 against one another for the samepurpose.

In the embodiment of FIGS. 4 and 5, the curl corrector rods 16,17 aremounted in plate-like mounting elements 183 which are formed in twoparts 184,185, hinged together at 45. Relative pivotal movement of thetwo parts 184,185 is effected by a diaphragm actuator 46. Openingmovement, for introduction of the web W, is limited by an end stop 47.When the parts 184,185 are closed together, the gap between the rods16,17 may be greater than the thickness of the web W, or the rods may beurged together so that the one supports the other.

Although'it is preferred to carry the mounting elements 18,181,183 onpivotal arms 21,22 they can be guided on rectilinear rails extending atright angles to the straight line path of the web between the pairs ofguide rollers. This is shown diagrammatically in FIG. 6 where thecorrector rods 16,17 are mounted in a carriage 51 which spans rails 52each side of the web path and perpendicular thereto mid-way between theguide roll pairs 10,11 and 13,14. The end plates 186 of the carriageform the mounting elements and have wheels or sliding shoes 53 thatco-operate with the rails 51.

We claim:

1. A curl corrector apparatus for operating on a continuous travellingweb of paper, cardboard or like material between two pairs of web guiderollers, comprising two similar curl corrector rods, mounting means forsaid rods for maintaining them on opposite sides of the path of the webbetween said pairs of web guide rollers, two pairs of support rollscarried by the mounting means, each pair being arranged side by side andcontacting an associated curl corrector rod on its side away from theweb, means for displacing said mounting means transversely to the pathof the web between opposite sides of the straight line path between thepairs of guide rollers for correction of curl in either direction, andguide means for the mounting means to maintain the latter in theirtransverse displacement so that the angle formed by the deflected pathof the web is always substantially bisected by the plane which passesthrough the axis of the curl corrector rod which is defleeting the weband equidistantly between its support rolls.

2. An apparatus according to claim 1, wherein the mounting means includea common mounting element at each end of the curl corrector rods and bywhich said rods are rotatably carried.

3. An apparatus according to claim 2, wherein said guide means includesa pivotal linkage comprising, for each mounting element, a pair ofnon-parallel swinging arms pivoted at one of their ends at spacedpositions on a fixed part of the apparatus adjacent to any of the pairsof guide rollers, and pivoted at their other ends at spaced positions onthe respective mounting element.

4. An apparatus according to claim 2, wherein said guide means includespivotal arms each pivoted at one end to a fixed part of the apparatusadjacent to one of the pairs of guide rollers, the other ends formingsaid mounting elements, and carrying one end of each of the two curlcorrector rods, links pivoted to the arms on the axes of the respectivecurl corrector rods and carrying said support rolls, and further linksconnecting the first mentioned links to spaced pivots on the fixed part.

5. An apparatus according to claim 2, wherein said guide means includesrails extending transversely to the straight line path between the pairsof guide rollers and on which the mounting elements are carried.

6. An apparatus according to claim 1, wherein means are provided forurging the two curl corrector rods against one another, so that the onewhich is not acting as a curl corrector at any given time will serve asan additional support roll for the one which is so acting.

1. A curl corrector apparatus for operating on a continuous travellingweb of paper, cardboard or like material between two pairs of web guiderollers, comprising two similar curl corrector rods, mounting means forsaid rods for maintaining them on opposite sides of the path of the webbetween said pairs of web guide rollers, two pairs of support rollscarried by the mounting means, each pair being arranged side by side andcontacting an associated curl corrector rod on its side away from theweb, means for displacing said mounting means transversely to the pathof the web between opposiTe sides of the straight line path between thepairs of guide rollers for correction of curl in either direction, andguide means for the mounting means to maintain the latter in theirtransverse displacement so that the angle formed by the deflected pathof the web is always substantially bisected by the plane which passesthrough the axis of the curl corrector rod which is deflecting the weband equidistantly between its support rolls.
 2. An apparatus accordingto claim 1, wherein the mounting means include a common mounting elementat each end of the curl corrector rods and by which said rods arerotatably carried.
 3. An apparatus according to claim 2, wherein saidguide means includes a pivotal linkage comprising, for each mountingelement, a pair of non-parallel swinging arms pivoted at one of theirends at spaced positions on a fixed part of the apparatus adjacent toany of the pairs of guide rollers, and pivoted at their other ends atspaced positions on the respective mounting element.
 4. An apparatusaccording to claim 2, wherein said guide means includes pivotal armseach pivoted at one end to a fixed part of the apparatus adjacent to oneof the pairs of guide rollers, the other ends forming said mountingelements, and carrying one end of each of the two curl corrector rods,links pivoted to the arms on the axes of the respective curl correctorrods and carrying said support rolls, and further links connecting thefirst mentioned links to spaced pivots on the fixed part.
 5. Anapparatus according to claim 2, wherein said guide means includes railsextending transversely to the straight line path between the pairs ofguide rollers and on which the mounting elements are carried.
 6. Anapparatus according to claim 1, wherein means are provided for urgingthe two curl corrector rods against one another, so that the one whichis not acting as a curl corrector at any given time will serve as anadditional support roll for the one which is so acting.